The 1926 Auburn 66 Series comes from an era when American cars were moving quickly from purely utilitarian transportation toward more stylish and refined touring machines. Auburn’s mid-1920s offerings appeal to collectors who appreciate brass-era influence giving way to more modern proportions, road manners, and coachwork. For this exact model, tire selection centers on two bias-ply sizes, 30X5.25 and 5.25-20, so the first step is confirming which wheel and tire specification your car actually uses. That choice also shapes the look of the car, since both sizes reflect distinct early tire-sizing conventions. For restoration and road use alike, wheel diameter and overall fitment verification matter before any replacement is chosen.
Which Tire Size Is Right for The 1926 Auburn 66 Series
The 1926 Auburn 66 Series uses two primary tire sizes, and they do not share the same rim diameter. One fitment is 30X5.25 and the other is 5.25-20, both in bias-ply construction, so the most important first step is confirming which wheel setup is on the car. Once wheel diameter is settled, the decision becomes choosing the proper period-style tire format for the way the vehicle is restored and driven.
30X5.25 is an antique diameter-by-section size, meaning the first number refers to the tire’s approximate overall outside diameter and the second number refers to its approximate section width. On the 1926 Auburn 66 Series, this is a bias-ply fitment that reflects an earlier style of tire sizing than many modern buyers are used to seeing. Its appeal is closely tied to traditional pre-war presentation, where maintaining the proper visual proportion of the tire can matter as much as the basic fit. This size should be evaluated carefully against the car’s actual wheel dimensions before replacement.
5.25-20 is a numeric bias-ply size in which 5.25 represents the nominal section width in inches and 20 identifies the rim diameter. For the 1926 Auburn 66 Series, this format points to a more familiar vintage bias-ply sizing system built around a 20-inch wheel. It is a useful choice for owners who are matching the car to an established wheel specification and want a tire that stays within a traditional construction type. Confirming the actual wheel diameter on the vehicle is essential before selecting this size, especially on older cars that may have seen changes over time.
Sub-model fitment is straightforward here because the covered 6 Cyl. configuration is associated with the same two primary bias-ply size families used on the 1926 Auburn 66 Series. The key is not trim level but verifying which wheel and tire specification is actually on the car before choosing a replacement.
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1926 Auburn 66 Series 6 Cyl.
The 1926 Auburn 66 Series 6 Cyl. can use either 30X5.25 or 5.25-20 in bias-ply construction, making wheel confirmation the critical first step. Once that is settled, tire selection becomes a matter of matching the car’s existing setup and preserving the period-style appearance appropriate to an older restoration.
The tire sizes listed on this page assume factory-standard vehicle configuration. The following modifications may affect tire fitment and are not reflected in this guide:
Suspension changes (lowering, lift kits, spring replacements)
Body alterations (fender modifications, custom bodywork)
If your vehicle has been modified from factory specifications, verify tire clearance before purchase.
Frequently Asked Questions
Common questions for the 1926 Auburn 66 Series usually center on its two vintage tire sizes, the difference between early sizing formats, wheel-diameter confirmation, and what to inspect before putting an older collector car back on the road.
Tire Size & Fitment
What tire size fits a 1926 Auburn 66 Series?
The 1926 Auburn 66 Series uses two primary bias-ply tire sizes: 30X5.25 and 5.25-20. Those are not two modern interchangeable labels for the same tire; they represent different vintage sizing conventions and different wheel fitment paths for the car.
Choosing the right one starts with confirming the wheel diameter and the setup currently on the vehicle. Older collector cars are often restored, repaired, or updated over time, so the tire on the car today may not tell the whole story. Check the wheels themselves, compare the existing tire markings, and make sure the replacement matches the actual wheel and vehicle clearance requirements.
What size rim does a 1926 Auburn 66 Series use?
The 1926 Auburn 66 Series appears with two rim-diameter paths tied to its primary tire sizes. The 30X5.25 fitment is associated with a 5.0-inch rim diameter, while the 5.25-20 fitment uses a 20-inch rim diameter.
That makes wheel confirmation more important than simply matching a tire by appearance. On an antique vehicle, replacement wheels, mismatched spare assemblies, or older restoration work can create confusion. Measure the wheel, verify the stamping if present, and compare it with the tire size currently mounted before selecting a new tire. A correct tire choice starts with the actual rim the Auburn is using now.
What does 30X5.25 mean on a 1926 Auburn 66 Series?
30X5.25 is an antique diameter-by-section size. The 30 refers to the tire’s approximate overall outside diameter in inches, and 5.25 refers to the approximate section width rather than the rim diameter.
That sizing format is common on older vehicles and can be confusing if you are more familiar with later numeric bias-ply or modern radial markings. On a 1926 Auburn 66 Series, understanding that difference helps prevent ordering a tire by width alone. It is wise to confirm the wheel specification and compare the tire marking exactly, since antique-format sizes describe the tire differently from later 20-inch-rim numeric sizes.
Choosing the Right Tire
What should I consider when choosing a tire for a 1926 Auburn 66 Series?
Start with the actual tire size and wheel setup on the car, since the 1926 Auburn 66 Series can use either 30X5.25 or 5.25-20, both in bias-ply construction. The first decision is not brand or appearance, but matching the tire to the correct wheel specification.
After size and wheel diameter are confirmed, think about the type of restoration and driving the car sees. A vehicle shown for traditional presentation may call for a different visual approach than one prepared mainly for occasional road use. Also inspect wheel condition, make sure the tires clear fenders and steering components, and avoid assuming an older replacement already on the car is the correct reference.
How do I choose between the available 30X5.25 and 5.25-20 tires for a 1926 Auburn 66 Series?
The choice between 30X5.25 and 5.25-20 is determined by the car’s actual wheel and fitment specification, not by preference alone. Both are correct-format bias-ply sizes for this model, but they belong to different sizing systems and do not serve the same wheel arrangement.
A good approach is to verify the wheel diameter first and then compare the tire size marking exactly to what the car is set up to use. That keeps the selection process focused and helps preserve the vehicle’s stance and presentation. On a car of this age, wheel swaps and long-ago repairs are common enough that physical verification matters more than assumption.
Why does the 1926 Auburn 66 Series have more than one tire size?
The 1926 Auburn 66 Series appears with two primary tire sizes because early vehicles often used more than one sizing convention during their service life and restoration history. Here, the fitments are 30X5.25 and 5.25-20, both bias-ply, but they reference different wheel and tire formats.
That means the buyer’s job is to identify the actual setup on the individual car rather than treat both sizes as universally interchangeable. Antique vehicles may have accumulated replacement wheels, mixed spares, or earlier restoration choices that changed the tire path. Confirming wheel diameter and matching the size code exactly is the best way to sort out which fitment belongs on your Auburn.
Restoration & Appearance
Which tire should I choose for a period-style 1926 Auburn 66 Series?
A period-style choice for a 1926 Auburn 66 Series begins with using the correct vintage size format already matched to the car’s wheel setup. That means selecting either 30X5.25 or 5.25-20 in bias-ply construction, depending on which specification the vehicle actually carries.
Appearance on a mid-1920s car is shaped heavily by tire profile and proportion, so the size itself is part of the restoration decision. If exact originality matters, compare the car against marque-club guidance, restoration records, and other authoritative references tied to the individual vehicle. Even when the goal is not concours judging, keeping the proper size format helps preserve the Auburn’s authentic visual character.
Does correct tire fitment matter for a 1926 Auburn 66 Series restoration?
Correct tire fitment matters a great deal on a 1926 Auburn 66 Series because the tire contributes heavily to both stance and period presentation. Using the proper bias-ply size format, whether 30X5.25 or 5.25-20, helps keep the car visually in step with its era.
Fitment also affects practical details such as wheel compatibility and how the tire sits within the fender opening. A restoration can look noticeably off when the tire diameter, section width, or wheel relationship is not appropriate for the car’s setup. Verifying the actual wheels on the vehicle is especially important before replacing tires on an older Auburn that may have changed over decades.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1926 Auburn 66 Series?
Yes. Modifications can affect tire fitment on a 1926 Auburn 66 Series, especially because this car already appears with two different vintage tire-size paths. Changes to wheels, hubs, suspension components, brake hardware, or body clearances can alter which tire size works properly on the car.
An Auburn that has been restored over many decades may not match its earlier configuration in every detail. Check wheel diameter, inspect wheel width and condition, and turn the steering through its range to confirm clearance before mounting new tires. Even seemingly small changes can matter on an antique car where fender openings, ride height, and wheel hardware leave little room for assumption.
What should I inspect before driving a 1926 Auburn 66 Series on new tires?
Before road use, inspect the wheels, lug hardware, valve stems, and the mounted tires themselves. Make sure the tire size matches the wheel correctly, then look for proper seating, visible sidewall irregularities, air loss, and any contact points that could appear with steering or suspension movement.
A collector car that has spent long periods parked deserves a broader check beyond the tires alone. Examine brakes, wheel bearings, steering components, and suspension condition so the new tires are not being asked to compensate for other problems. A short, careful shakedown drive is a sensible next step, followed by another inspection for clearance marks, pressure loss, or loosened hardware.
How should tires on a collector 1926 Auburn 66 Series be maintained?
Tires on a collector 1926 Auburn 66 Series should be kept properly inflated, inspected regularly, and protected from long exposure to heat, sunlight, moisture, and ozone sources. Even when tread wear is minimal, antique and collector vehicles can develop age-related issues such as cracking, flat spotting, or internal deterioration from long storage.
Routine inspection matters more than mileage on a car that is driven occasionally. Look closely at sidewalls, tread surfaces, and the bead area, and check for any slow air loss before each outing. It also helps to move the car periodically during storage and keep the suspension and steering in good condition, since tire life and road manners are closely tied to the vehicle underneath.
